The pair have had plenty of romps with romantic comedy, though few have caused them to reflect seriously on their past loves. There's no escaping romantic history, however, with the Dickens-inspired Ghosts of Girlfriends Past, opening Friday. McConaughey stars as a heartless Casanova-type who gets his comeuppance when he is visited by spectral visions of his many flings. Garner is the long-ago love of his life, who may be about to find another soul mate.

These days, the actors are both in stable and well-known romances. Garner, who just turned 37, is married to Ben Affleck, her co-star from Daredevil, and they have two daughters, Violet, 3, and Seraphina, almost 5 months. McConaughey, 39, is with Brazilian model Camila Alves, who gave birth to his son, Levi, who turns 1 in July.

They've also had high-profile breakups. Garner used to date Alias co-star Michael Vartan and was previously married to Felicity co-star Scott Foley, while McConaughey began dating Penelope Cruz when they made Sahara and Sandra Bullock when they made A Time to Kill.

They don't name names but do speak candidly about how past relationships have shaped them — and how love changes as you grow from a teenager to a parent.

McConaughey mentions a scene in which Garner's character wakes up alone after spending the night with him. "He gets to go back and see what happened after she woke up. I'd be willing to say I've been there. I saw that and know I felt a little bit of that. I've had to end good relationships, and I know how we talked about them, and tried to be nice and everything, but I think ... maybe that bruised a little bit more on the other side than I noticed, or than it did me."

He leans in on his elbow and says, in a confidential tone: "Because when you flip it over, I know there were times when I was the dumpee or whatever, and I was like, 'No way am I showing her how much this is hurtin'.' "

McConaughey's cowboyish self-assurance fades as he considers the ramifications of being an invisible eyewitness to some of his own breakups: "There's that old saying about three truths: what I say, what you say and what really happened. You never know how the other person really took it. You get behind the closed door, and you can see how your actions affected someone."

Remembering first dates

During filming, the pair often talked about whether they would, if it were possible, go backward or forward in time to re-examine old or future relationships.

"Jennifer said, 'Yeah, I would go forward, but not if I'm going to see a disaster that I can't effect now,' " McConaughey says.

"Just to see it?" she adds, shaking her head. "No, I don't want to see it."

"The more interesting question is about going back," he says. "Ghosts from your past or whatever ..."

McConaughey goes back — way back — to some of his first experiences with romantic relationships.

"Those first times, though, I knew how to handle it," McConaughey boasts with a grin. "We went to see a movie once, and slowly this right hand started moving." Sitting beside Garner, he begins an infinitesimally slow drape across her shoulders. "It took me the entire movie to get there, and then the credits rolled. I was so concentrated on just getting there, I didn't see one frame of the movie."

"How far down did you get? Inside bra?" Garner says, calling him out on his vagueness.

"Yep," he says, nodding. "And then the credits rolled."

Garner laughs and says, "She probably spent the whole time thinking, 'Am I going to brush that hand off? Am I going to move?' She probably had to pee, but was like, 'Well, no, because then he'd have to start from scratch.' "

"Girls just play defense," Garner offers. "Guys are the chaser and pursuer." Neither role is easier, she adds.

"I think it's different now than it was when we were going through this," she says. "It's more equal. But when we were kids, you didn't just call a guy. At least not a nice girl."

"No, you didn't call," McConaughey agrees, like someone who remembers it well.

"There was no texting or IMing or anything. Your friends could go ask his friends if he was interested, but that was all," she says. "You'd send your secretary of state out."

"But the funnest and the hardest moments," McConaughey says, "was the one where you go up and say, 'Will you go with me?' Just say those words, and then she says, 'Yes.' And I'd be like ... 'Great! Now what comes next?' "

Shared tastes and talents

If these two weren't otherwise attached, it would be easy to see them together. Both sit at an upstairs table at an organic vegan restaurant, a little chagrined by the menu.

"They told me you loved this place," she says, when McConaughey doesn't have a meal recommendation.

"I've never been here before," he says. "They told me you loved this place."

While she projects precision, poise and efficiency, and his languid, surfer-stoner aura is the real deal, they bond while dissecting a pulled-pork sandwich recipe she made the weekend before and progress to sharing a mutual love of cooking. And they are both big eaters.

When the waiter returns, she orders a Southwestern vegetable meal and asks for it to be combined with the Mexicali salad. "Would it be the hugest thing ever?" she asks.

The waiter tells her yes.

McConaughey grins at Garner. "You just kind of ordered for me. I was going to do the same thing."

"I've never had a meal with you, but I feel like I could order for you," she says, explaining that they used to pass the downtime on set with "long, slow description of how a meal was prepared, what was in it, how it was mixed, how it was eaten."

If they actually were a couple, it's likely the lean and seductive stars would eventually inflate each other to Pavarotti proportions.

Love vs. power

The twosome, looking back on how they ended up with their current mates, realize it was a fairly deliberate process.

"That's what growing up and boyfriends, girlfriends and all the painful relationships are all for," McConaughey says. "Each one is its own lesson."

When dating after age 25, McConaughey says, he was on the lookout for "traits of someone you may possibly spend the rest of your life with. You're looking for traits in this person that you would want to be the mother of your child. ... If something came up that didn't qualify for me, I was out."

Says Garner: "I would say the same for women looking at the relationship. You're trying to figure out if the person can be a mate."

McConaughey cuts in to clarify one thing: "When I was talking about women I wanted to date," he says, laughing coyly, "(a potential mother) was not always what I was looking for. There were times when you're a guy when it's not about 'a relationship.' It's about —" He fumbles with his words but traces a shapely invisible female silhouette in the air.

Though Ghosts of Girlfriends Past is mostly a silly time-travel trip backward and forward through the life of a playboy charmer, there's one line in the movie that McConaughey thinks strikes at something real: "Whoever cares less has the most power. A lot of people have been bringing that one up," he says. "And it's true."

"It's true, but is it the goal?" Garner asks.

"Depends on if power is what you're after. I think that's a good question. For some people power is the end all," McConaughey says.

Any of those types among his own past girlfriends?

"Hell, yeah. I've dated some of them and also been the one!" he replies.

"I've been the one, too," Garner adds. "It shifts back and forth when you've been with somebody for a long time, without even realizing that power is something you're after. It's fluid. You have to remind yourself sometimes 'Why am I fighting over this?' "

Having kids, they say, does change the romantic equation.

Garner says parenthood makes a couple stronger. "You've got something pretty major in common — a baby," Garner says. "And nobody else cares about this little critter more than you two do. This little person means more to you than anything in the world."

"Still, the one you made 'em with still better be No. 1," McConaughey cautions. "A lot of relationships blow up. I've seen it happen. They have the child, then all of a sudden the mother says, 'Oh my God, this kid is just my entire life, and that's it.' Dad was No. 2, and it didn't end up being very good for the kid or the relationship. There's a great line about how the best example you can give the kids is show them how you love their mother, or how you love their father."

No romance is perfect, but these romantic-comedy stars say it's important to try the best you can — there is no going back to change things in real life.

"Without being too philosophical about it, I look back, and it's easy to sit here now and say, 'Look, I wouldn't change any of the past — the victories, the glories or the pain," McConaughey says. " 'Cause they helped me get to where I am today."

To report corrections and clarifications, contact Reader Editor Brent Jones. For publication consideration in the newspaper, send comments to letters@usatoday.com. Include name, phone number, city and state for verification. To view our corrections, go to corrections.usatoday.com.

Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more.